Hard Drive Disaster Recovery Help

My 160 GB Win7 drive on my laptop failed (single partition), but thankfully I had a backup that I created on a 750 GB drive using EASUS Partition Master COPY. The backup drive is FULLY BOOTABLE, I've been booting into Windows 7 from an eSata external interface with no issues. It has a partition with my backed up Win7 installation and the rest is just unallocated space

My problem is restoring the backup to my new 160 GB drive. I've tried every which way to copy the partition over but it's never bootable - when I try to repair from the Windows CD using the GUI or command line tools it never works out.

HELP!

The big problem is that the backup drive is 5 times bigger than my new drive. How do I copy my entire windows installation so that it's bootable?